A robust in vitro screening assay to identify NF-κB inhibitors for inflammatory muscle diseases

Specific therapies are not available for inflammatory muscle diseases. We and others have shown that the pro-inflammatory NF-κB pathway is highly activated in these conditions. Since NF-κB is an important therapeutic target, we decided to utilize an in vitro screening assay to identify potential inhibitors that block TNF-α induced NF-κB activation in a C2C12 muscle line stably expressing an NF-κB luciferase reporter gene. Upon evaluation of multiple anti-inflammatory agents in undifferentiated myoblasts as well as differentiated myotubes , we found different levels of inhibition depending on the state of differentiation. Interestingly, we found that some drugs that are known to inhibit NF-κB in immune cells were not effective in muscle cells. Drug toxicity was assessed for using an MTT cell viability assay, and the validity of the luciferase assay was verified by immunostaining for NF-κB nuclear translocation in myoblasts. In conclusion, we have determined the optimal assay conditions for detecting potentially valuable NF-κB inhibitors for the first time in a muscle cell line that may have significant therapeutic potential for inflammatory muscle diseases.     

Study on anti-androgenic effects of bisphenol a diglycidyl ether (BADGE), bisphenol F diglycidyl ether (BFDGE) and their derivatives using cells stably transfected with human androgen receptor, AR-EcoScreen.

We studied in vitro hormonal activity of bisphenol A diglycidyl ether (BADGE) and bisphenol F diglycidyl ether (BFDGE), which are used as a material of interior coating for food cans. We also examined related compounds such as 2,2-bis[4-(3-chloro-2-hydroxypropoxy)phenyl]propane (BADGE.2HCl), and bis[4-(3-chloro-2-hydroxypropoxy)phenyl]methane (BFDGE.2HCl) etc. For this purpose, we constructed two stably transfected CHO-K1 cell lines (AR-EcoScreen for androgenic activity and c-luc for cell toxicity evaluation). One stably expresses luciferase with induction of androgen. The other stably expresses luciferase without androgen induction. Also, we have determined the androgenic and anti-androgenic effects of the test chemicals by reporter gene assay with these cell lines. None of the chemicals tested by this assay exhibited androgen agonistic activity. However, BADGE.2HCl and BFDGE.2HCl had the conspicuous antagonistic activity for androgen. These compounds had a high binding affinity for androgen receptor. Furthermore, these two compounds did not show the estrogenic activity in vitro assays. On the contrary, bisphenol A and bisphenol F exhibited anti-androgenic activity in vitro in addition to the estrogenic activity. These results suggest that these chlorohydroxy compounds of BADGE and BFDGE act as androgen antagonist through the process of binding to androgen receptor.     

Nfic 基因 3′UTR 双荧光素酶报告质粒的构建及其与 miR-20a 靶向关系的验证

摘要： 目的 构建核因子 C（nuclear factor I-C, Nfic）基因 3′非编码区（3′UTR）荧光素酶报告质粒, 利用双荧光素酶报告基因验证 microRNA-20a（miR-20a）与其潜在靶基因 Nfic 的靶向关系。 方法 通过 microRNA 靶基因预测软件 Targetscan 获取 miR-20a 与 Nfic 基因 3′UTR 潜在的互补结合位点; PCR 扩增出 Nfic 基因 3′UTR 序列, 将此序列克隆至荧光素酶报告载体 pMIR-Report Luciferase; 将重组荧光素酶报告质粒与 miR-20a mimics（ 实验组） 或 NC mimics（对照组）共同转染 293-AD 细胞, 收集细胞后通过双荧光素酶报告系统检测 2 组细胞的荧光素酶活性, 从而对 Nfic 与 miR-20a 的靶向调节关系进行鉴定。 将 miR-20a mimics 和 NC mimics 分别转染骨髓基质细胞系 ST2, 裂解细胞提取蛋白后采用 Western blotting 检测 NFIC 蛋白的表达水平。 结果 构建的重组荧光素酶报告质粒经酶切及测序鉴定正确。 双荧光素酶报告基因检测显示, 与对照组相比, miR-20a 可以抑制 Nfic 3′UTR 报告基因载体的荧光素酶活性（P < 0.05）;Western blotting 结果显示, 与对照组相比, ST2 细胞转染 miR-20a mimics 后 NFIC 蛋白表达水平明显下调。 结论 成功构建了 Nfic 基因 3′UTR 荧光素酶报告质粒,而 miR-20a 可以直接作用于 Nfic 基因 3′UTR,抑制其荧光素酶活性。     

A cell-based assay for IkappaBalpha stabilization using a two-color dual luciferase-based sensor

A cell-sensor assay for stabilization of IkappaBalpha was developed in the activated B cell-like diffuse large B-cell lymphoma cell line OCI-Ly3. This cell line expresses known nuclear factor kappaB (NFkappaB) target genes due to high constitutive activity of IkappaB kinase (IKK), which phosphorylates the protein IkappaBalpha leading to proteasomal degradation of IkappaBalpha and activation of NFkappaB. The cell-sensor assay uses green and red light-emitting beetle luciferases, with the green luciferase fused to IkappaBalpha (IkappaBalpha-CBG68) and the red luciferase (CBR) present in its native state. The IkappaBalpha-CBG68 reporter functions as a sensor of IKK and proteasome activity, while CBR serves to normalize for cell number and nonspecific effects. Both reporter constructs were stably integrated and placed under the control of an inducible promoter system, which increased fold responsiveness to inhibitors when assay incubations were performed simultaneous to reporter induction by doxycycline. The assay was miniaturized to a 1,536-well plate format and showed a Z' of 0.6; it was then used to panel 2,677 bioactive compounds by a concentration-response-based screening strategy. The concentration-effect curves for the IkappaBalpha-CBG68 and CBR signals were then used to identify specific stabilizers of IkappaBalpha, such as IKK inhibitors or proteasome inhibitors, which increased the doxycycline-induced rise in IkappaBalpha-CBG68 without affecting the rise in CBR. Known and unexpected inhibitors of NFkappaB signaling were identified from the bioactive collection. We describe here the development and performance of this assay, and discuss the merits of its specific features.     

Characterization of a reliable cell-based reporter gene assay for measuring bioactivities of therapeutic anti-interleukin-23 monoclonal antibodies

Environmental disturbances may result in dysregulation of interleukin-23 (IL-23), which is a crucial modulator of immunity. Several therapeutic monoclonal antibodies (mAbs) have been developed for treating IL-23-related autoimmune inflammation, such as ustekinumab, guselkumab, tildrakizumab, and risankizumab. Accurate bioactivity determination of therapeutic mAbs is essential for their quality control and clinical application. However, the current methods are tedious and complicated. In the present study, we employed low-background lentivirus carrying sis-inducible element (SIE)-driven firefly luciferase to generate a stable DB-SIE-Luc cell line that expresses endogenous IL-23 receptors and developed a sensitive and straightforward reporter gene assay (RGA) based on DB-SIE-Luc cells. After the optimization of various assay parameters, we set up a bioassay with the best fit of a four-parameter model and an appropriate signal-to-noise ratio (SNR) for bioactivity determination of guselkumab. We further verified the excellent assay performance characteristics of our RGA, including specificity, linearity, accuracy, precision, and stability, according to ICH-Q2. Taken together, we established a reliable and robust cell-based RGA, which potentially serves as a valubale alternative bioactivity determination assay for the release control and stability study of anti-IL-23 mAbs.     

miR-149抑制结直肠癌细胞迁移的分子机制研究

目的 探讨miR-149对结直肠癌（CRC）细胞增殖、侵袭、迁移及凋亡的影响及其作用机制。方法 实时荧 光定量PCR（q-PCR）方法检测miR-149在CRC细胞SW620、LS174T和人结肠上皮细胞FHC中的表达水平;荧光素酶 分析法验证 STAT3 与 miR-149 之间的靶向结合关系;q-PCR 和 Western blot 检测 miR-149 过表达对 CRC 细胞中 STAT3、p-STAT3 mRNA和蛋白表达的影响。将miR-149 mimics与STAT3过表达质粒单独或者共转染至CRC细胞 中,并分为miR-NC组、miR-149 mimics组、miR-149 mimics+pEGFP/STAT3组。采用CCK-8法、Transwell法、细胞划 痕法、流式细胞术分别检测各分组CRC细胞的增殖、侵袭、迁移和凋亡情况。结果 与正常结肠上皮细胞FHC相比, CRC 细胞 SW620、LS174T 中 miR-149 表达水平受到抑制（P＜0.01）。荧光素酶实验证实,在 CRC 细胞中 STAT3 是 miR-149的一个直接靶基因。过量表达miR-149抑制STAT3、p-STAT3 mRNA和蛋白的表达,降低CRC细胞增殖能 力、侵袭能力以及迁移能力（P＜0.01）。同时,过量表达 miR-149 也可促进 CRC 细胞的凋亡（P＜0.01）。但过表达 STAT3可解除miR-149对CRC细胞增殖、侵袭以及迁移能力的抑制作用。结论 miR-149通过靶向STAT3抑制结直 肠癌细胞的增殖、侵袭与迁移,同时促进细胞的凋亡。     

5-羟色胺1A受体激动剂高通量筛选模型的建立

目的为发现5-羟色胺1A(5-HT1A)受体的激动剂,通过报告基因活性检测的方法建立高通量筛选(HTS)细胞模型。方法将带有人源5-HT1A受体的真核表达质粒pcD-NA3.1(pcDNA3.1-h5-HT1AR)与带有报告基因pCRE-luc的pcDNA3.1质粒(pcDNA3.1-pCRE-luc)共转染到工具细胞中,通过对工具细胞选择、共转染质粒比例、化合物孵育时间及阳性化合物选择等条件进行探索和优化,建立了稳定表达人源5-HT1A受体并可用于该受体激动剂筛选的细胞模型(HEK293-h5-HT1AR)。结果①根据瞬转实验中信号值的高低,模型采用HEK293细胞作为工具细胞;②根据瞬转实验中的信噪比,发现pcDNA3.1-h5-HT1AR:pcDNA3.1-pCRE-luc的最佳比例为1∶3;③对化合物孵育时间进行优化,选择的最佳孵育时间为6 h;④阳性化合物的选择过程中,实验研究了5-HT.HCl,Flibanserin,8-OH-DPAT以及Lorcaser-in(APD356)4个已报道有5-HT1A受体激动活性的化合物,结果表明APD356在该体系中最适合作为阳性对照化合物。⑤该细胞株连续培养12代,信号稳定。结论通过对一系列实验条件进行选择和优化,建立了一个稳定表达人源5-HT1A受体的细胞模型,该模型可用于高通量5-HT1A激动剂的筛选。     

靶向CD19嵌合抗原受体T细胞体外构建、扩增及抗肿瘤活性研究

目的  探索特异性靶向CD19的嵌合抗原受体（chimeric antigen receptor, CAR）T细胞的构建与制备方法,并研究其体外杀伤靶细胞的效果。方法  通过基因合成和分子克隆手段构建anti-CD19-CAR片段并将其插入plenti6.3慢病毒载体,利用293FT悬浮细胞系包装慢病毒并转染人外周血单个核细胞来源的CD3⁺ T细胞,通过流式细胞术鉴定转染效率,并通过实时无标记细胞分析法和细胞计数试剂盒8检测anti-CD19-CAR-T细胞体外杀伤效果。结果  获得了表达抗CD19的单链抗体基因的慢病毒,病毒滴度可达3.2×10⁸ 噬斑形成单位/ml。经慢病毒转染的CD3⁺ T细胞在体外培养14 d后,细胞扩增效率达(60.2±11.5)倍,anti-CD19-CAR-T细胞阳性率达90.57%。经检测,anti-CD19-CAR-T细胞均可有效杀伤CD19⁺靶细胞。结论  建立了基于无血清悬浮细胞系的anti-CD19-CAR慢病毒包装系统,成功构建靶向CD19抗原的CAR-T细胞,能特异性杀伤CD19+肿瘤细胞。     

Development and characterization of a stable luciferase dengue virus for high-throughput screening

To facilitate dengue virus (DENV) drug discovery, we developed a stable luciferase reporter DENV-2. A renilla luciferase gene was engineered into the capsid-coding region of an infectious cDNA clone of DENV-2. Transfection of BHK-21 cells with the cDNA clone-derived RNA generated high titers (>10⁶ PFU/ml) of luciferase reporter DENV-2. The reporter virus was infectious to a variety of cells, producing robust luciferase signals. Compared with wild-type virus, the reporter virus replicated slower in both mammalian Vero and mosquito C6/36 cells. To examine the stability of the reporter virus, we continuously passaged the virus on Vero cells for five rounds. All passaged viruses stably maintained the luciferase gene, demonstrating the stability of the reporter virus. Furthermore, we found that the passaged virus accumulated a mutation (T108M) in viral NS4B gene that could enhance viral RNA replication in a cell-type specific manner. Using the reporter virus, we developed a HTS assay in a 384-well format. The HTS assay was validated with known DENV inhibitors and showed a robust Z′ factor of 0.79. The Luc-DENV-2 HTS assay allows screening for inhibitors of all steps of the viral life cycle. The reporter virus will also be a useful tool for studying DENV replication and pathogenesis.     

高通量筛选JAK-STAT6信号传导通路抑制剂方法的初步建立

目的构建可用于高通量筛选JAK/STAT6信号传导通路抑制剂的工程细胞株,建立稳定可靠的筛选方法。方法利用基因重组和转染技术,将STAT6特异性识别启动子IgE基因序列和虫荧光素酶报告基因联合插入pCMV质粒,脂质体法转染至HeLa细胞,经潮红霉素B抗性筛选及报告基因检测,得到稳定表达虫荧光素酶的工程细胞株。通过优化溶剂DMSO浓度,IL4作用浓度及孵育时间等筛选条件,建立了可靠的筛选方法,并在此基础上对1600种化合物进行了筛选。结果建立的筛选方法稳定可靠,系统Z′因子达到0.64。通过对1600种化合物的筛选,得到3个抑制效果较理想的化合物并测得其IC50值。结论所建立的高通量筛选方法可用于JAK/STAT6信号传导通路抑制剂的筛选。     

Preparation and characterization of polymeric nanoparticles for siRNA delivery to down-regulate the expressions of exogenous and endogenous target genes

Gene silencing induced by RNA interference using small interfering RNA (siRNA) provides a promising therapeutic approach for cancers. However, the lack of siRNA delivery vector has limited the development of siRNA therapy. The purpose of this study was to use the novel copolymer (mPEG5k-PCL1.2k)1.4-g-PEl10k to prepare siRNA-loaded nanoparticles for siRNA delivery. The results suggested that (mPEG5k-PCL1.2k)1.4-g-PEl10k could load siRNA to form nanoparticles with particle size less than 200 nm in a narrow distribution. Moreover, a certain density of positive charge existed onto the surfaces of nanoparticles. MTT assay results demonstrated that (mPEG5k-PCL1.2k)1.4-g-PEl10k/siRNA nanoparticles showed very low cytotoxicity. The gene silencing efficiency of (mPEG5k-PCL1.2k)1.4-g-PEl10k/siRNA nanoparticles was investigated through luciferase reporter gene assays. The expression of exogenous luciferase gene was significantly downregulated at a range of N/P ratio from 50 to 125, and was maximally inhibited at the N/P ratio of 125 with 54% and 59% reduction in MCF-7 and HepG2 cells, respectively. In the 4T1-luc cell line expressing luciferase stably, the silencing of endogenous luciferase gene also has a similar overall profile with maximal 54% reduction of luciferase expression. These results suggested that (mPEG5k-PCL1.2k)1.4-g-PEI10k/SiRNA nanoparticles could serve as a kind of highly efficient siRNA delivery system for down-regulating the expression of exogenous and endogenous target genes.     

Development of a stably transfected estrogen receptor-mediated luciferase reporter gene assay in the human T47D breast cancer cell line.

Development of an estrogen receptor-mediated, chemical-activated luciferase reporter gene-expression (ER-CALUX) assay was attempted by stable transfection of luciferase reporter genes in a number of cell lines. Stable transfection of the chimeric Gal4 estrogen receptor and luciferase gene constructs in MCF-7 breast cancer and Hepa.1c1c7 mouse hepatoma cell lines, as well as transfection of a newly constructed luciferase reporter gene pEREtata-Luc in the ECC-1 human endometrial cell line, resulted in constitutive, non-estradiol-inducible clones. Stable transfection of pEREtata-Luc in the T47D breast cancer cell line, however, resulted in an extremely sensitive, highly responsive cell line. Following a 24-h exposure to estradiol (E2), stably transfected T47D.Luc cells demonstrated a detection limit of 0.5 pM, an EC50 of 6 pM, and a maximum induction of 100-fold relative to solvent controls. No clear reduction in responsiveness has been found over extended culture periods (50 passages). Anti-estrogens ICI 182,780, TCDD, and tamoxifen inhibited the estradiol-mediated luciferase induction. Genistein, nonylphenol, and o,p'DDT were the most potent (pseudo-)estrogens tested in this system (EC50 100, 260, and 660 nM, respectively). Determination of interactive effects of the (pseudo-)estrogens nonylphenol, o,p'DDT, chlordane, endosulfan, dieldrin, and methoxychlor revealed that, in combination with 3 pM E2, (pseudo-)estrogens were additive. Slightly more than additive effects (less than 2-fold) were found for combinations of dieldrin and endosulfan tested in the range of 3 to 6 microM. At these concentrations, the combination of endosulfan and chlordane demonstrated additive interaction. The ER-CALUX assay with T47D cells can provide a sensitive, responsive, and rapid in vitro system to detect and measure substances with potential (anti-)estrogenic activity.     

Construction and characterization of monoclonal antibodies against the extracellular domain of B-lymphocyte antigen CD20 using DNA immunization method

To date, several new anti-CD20 monoclonal antibodies (mAbs) have been developed for potential efficacies compared with familiar mAb rituximab. Despite the recent advances in development of anti-CD20 mAbs for the treatment of B cell malignancies, the efforts should be continued to develop novel antibodies with improved properties. However, the development of mAbs against CD20 as a multi-transmembrane protein is challenging due to the difficulty of providing a lipid environment that can maintain native epitopes. To overcome this limitation, we describe a simple and efficient DNA immunization strategy for the construction of a novel anti-CD20 mAb with improved anti-tumour properties. Using a DNA immunization strategy that includes intradermal (i.d.) immunization with naked plasmid DNA encoding the CD20 gene, we generated the hybridoma cell line D4, which secretes functional mAbs against an extracellular epitope of CD20. Immunocytochemistry analysis and a cell-based enzyme-linked immunosorbent assay using a Burkitt's lymphoma cell line showed that D4 mAbs are capable of binding to native extracellular epitopes of CD20. Moreover, the binding specificity of D4 mAbs was determined by western blot analysis. Cell proliferation was examined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Apoptosis was detected by the annexin V/propidium iodide staining and dye exclusion assay. The results showed that D4 anti-CD20 mAbs produced by DNA immunization exhibit potent growth inhibitory activity and have superior direct B-cell cytotoxicity compared to rituximab. We propose that antibody-induced apoptosis is one of the mechanisms of cell growth inhibition. Taken together, the data reported here open the path to DNA-based immunization for generating pharmacologically active monoclonal antibodies against CD20. In addition, the data support future in vivo animal testing and subsequent procedures to produce a potential therapeutic mAb.     

The T-body approach: redirecting T cells with antibody specificity

"T-bodies" are genetically engineered T cells armed with chimeric receptors whose extracellular recognition unit is comprised of an antibody-derived recognition domain and whose intracellular region is derived from lymphocyte stimulating moiety(ies). The structure of the prototypic chimeric receptor, also known as a chimeric immune receptor, is modular, designed to accomodate various functional domains and thereby to enable choice of specificity and controlled activation of T cells. The preferred antibody-derived recognition unit is a single chain variable fragment (scFv) that combines the specificity and binding residues of both the heavy and light chain variable regions of a monoclonal antibody. The most common lymphocyte activation moieties include a T-cell costimulatory (e.g. CD28) domain in tandem with a T-cell triggering (e.g. CD3zeta) moiety. By arming effector lymphocytes (such as T cells and natural killer cells) with such chimeric receptors, the engineered cell is redirected with a predefined specificity to any desired target antigen, in a non-HLA restricted manner. Chimeric receptor (CR) constructs are introduced ex vivo into T cells from peripheral lymphocytes of a given patient using retroviral vectors. Following infusion of the resulting T-bodies back into the patient, they traffic, reach their target site, and upon interaction with their target cell or tissue, they undergo activation and perform their predefined effector function. Therapeutic targets for the T-body approach include cancer and HIV-infected cells, or autoimmune effector cells. To date, the most investigated area is cancer therapy. Here, the T-bodies are advantageous because their tumor recognition is not HLA-specific and, therefore, the same constructs can be used for a wide spectrum of patients and cancers.